The invention relates to an athermalized plastic lens.
In a system (e.g., a bar code scanner) that relies on a specific optical property (e.g., a specific focal length) of a lens, changes in temperature that affect the specific optical property of the lens can cause the system to function improperly or inaccurately. For example, if the lens is used in a bar code scanner to focus light reflected from a bar code symbol onto a CCD device that produces an image of the symbol, the produced image may be too out-of-focus to be effectively decoded if the focal length of the lens is affected significantly by a temperature change. Typically, a glass lens is more resistant to temperature changes than a plastic lens having the same shape.